MS/MS analysis is useful for identifying molecular species by acquiring information on a structure of precursor ions from a pattern of fragment ions. Further, the MS/MS analysis has been widely applied to quantitative analysis because an influence of noise caused due to impurities can be avoided. How to perform the above analysis according to the related art will be described below.
A method of performing MS/MS analysis using an ion trap unit is disclosed in U.S. Pat. No. 7,078,685. First, sample ions are introduced into an ion trap unit so as to be trapped. Next, all ions except for specific precursor ions among the trapped ions are ejected outside the trap. Then, the precursor ions remaining in the trap are dissociated by collision induced dissociation and the like, that collides the precursor ions with rare gas. Finally, fragment ions generated at the time of dissociating the precursor ions are extracted mass-selectively.
A method of performing MS/MS analysis using a mass spectrometer having a configuration where a collision induced dissociation portion is inserted between two quadrupole mass filters is disclosed in “Biomedical Mass Spectrometry Magazine, Volume 8, pp. 397 (1981)”. The quadruple mass filter in a first stage selectively transmits only specific precursor ions among ions, which are introduced into the mass spectrometer, and ejects all the other ions. Next, a collision induced dissociation portion dissociates the precursor ions by collision induced dissociation and the like, that collides the precursor ions with rare gas. The quadrupole mass filter in a second stage performs a mass analysis of fragment ions generated in the collision induced dissociation portion.
A method of performing MS/MS analysis using a mass spectrometer having a configuration where a collision induced dissociation portion is inserted between a quadrupole mass filter and a time-of-flight mass spectrometer is disclosed in “Rapid Communications in Mass Spectrometry Magazine Volume 10, pp. 889-896 (1996)”. The quadruple mass filter selectively transmits only specific precursor ions among ions, which are introduced into the mass spectrometer, and ejects all the other ions. Next, a collision induced dissociation portion dissociates the precursor ions by collision induced dissociation and the like, which collides the precursor ions with rare gas, to generate fragment ions. Then, fragment ions, which are generated by the collision induced dissociation portion, are introduced into the time-of-flight mass spectrometer, which performs mass analysis. This configuration can perform the mass analysis of the fragment ions having higher resolution than the configuration that performs the mass analysis of the fragment ions using the quadrupole mass filter, but is poor in view of the duty cycle.
A method of performing MS/MS analysis using a mass spectrometer having a configuration where a collision induced dissociation portion is inserted between two time-of-flight mass spectrometers is disclosed in U.S. Pat. No. 5,464,985. The time-of-flight mass spectrometer in a first stage performs a mass analysis of ions, which are introduced into the mass spectrometer, and introduces only specific precursor ions into a collision induced dissociation portion and ejects all the other ions. Next, a collision induced dissociation portion dissociates the precursor ions by collision induced dissociation and the like, that collides the precursor ions with rare gas. Then, the time-of-flight mass spectrometer in a second stage performs a mass analysis of fragment ions generated in the collision induced dissociation portion. This configuration can select the precursor ions having higher resolution than the configuration that selects the precursor ions using the quadrupole mass filter.
A method of performing a precursor scan or a neutral loss scan, which is a kind of MS/MS analysis using a mass spectrometer configured with a collision induced dissociation portion inserted between an ion trap unit and a time-of-flight mass spectrometer or between an ion trap unit and a quadrupole mass filter is disclosed in U.S. Pat. Nos. 6,504,148 and 6,507,019. First, ions, which are introduced into the mass spectrometer, are trapped in the ion trap unit. The trapped ions are sequentially extracted from the ion trap unit and then introduced into a collision induced dissociation portion. Next, the collision induced dissociation portion dissociates the precursor ions by collision induced dissociation and the like that collides the precursor ions with rare gas. Then, the time-of-flight mass spectrometer or the quadrupole mass filter performs a mass analysis of fragment ions generated in the collision induced dissociation portion. This configuration increases the duty cycle of the precursor ion scan or the neutral loss scan as compared to a case where the precursor ions are selected by the time-of-flight mass spectrometer or the quadrupole mass filter.